Car-bottom furnace



May 11, 1948. J. c. PIPER CARBOTTOM FURNACE Filed June 2, 1943 2 Sheets-Sheet 1 IN V EN TOR. a m

jab BY Patented May 11, 1948 OAR-BOTTOM FURNACE John C. Piper, Pittsburgh, Pa., assignor to Loftus Engineering Corporation, a corporation of Maryland Application June 2, 1943, Serial No. 489,363

Claims. 1

This invention relates to annealing and heat treating furnaces, particularly to car-bottom or car-type furnaces. The invention lies in improvements in construction.

A furnace of the sort herein held in contemplation includes a furnace chamber constructed of refractory brickwork, externally reinforced and tied, by means of structural steel and tie-rods. The floor of the furnace, upon which the articles to be heat treated are borne, comprises the body of a cara car that may be likened to a railway flat-car whose floor is constructed of refractory blocks. The car is adapted to travel on wheels or rollers between service position within the furnace chamber and loading and unloading position externally of such chamber. The front wall of the furnace is provided with a door which is opened and closed as need be, to permit of the said movement of the car into and out of the furnace chamber, and, alternately, to close the chamber for normal operation of the furnace.

When the furnace is in normal operation, fuel and air are projected in regulated quantities into the furnace chamber, maintaining combustion therein and heating to desired temperature the articles to be treated. The products of combustion find escape through suitable outgo ports that open through the walls of the furnace chamber, and communicate through suitable fiues to a stack or other vent. After the work has been heated at regulated rate to the required temperature, the combustion within the furnace is retarded or interrupted, and the work allowed to cool through the desired cooling cycle.

As indicated above, the upper surface of the car body provides the floor of the furnace chamber, and means are provided for sealing the car body along its two sides and inner or back end to the two side walls and back wall of the furnace, while, as already mentioned, the door of the furnace seats upon the outer or front end of the car body. Thus, the body of the car is sealed to the furnace walls, to provide in effect an integral furnace chamber in which the desired conditions of combustion and thermal head may be established and maintained.

More particularly, my invention consists in improvements in the means for sealing the body of the car to the walls of the furnace.

In the accompanying drawings,

Fig. I is a fragmentary view in perspective of a car-bottom furnace including in exemplary way an embodiment of the invention.

Fig. II is a fragmentary view-of the furnace nace, the burners, the Waste gas fiues, the mechstructure, as seen in horizontal section, on th plane 11-11 of Fig. III.

Fig. III is a fragmentary view of the furnace, as seen on the plane III-III of Fig. II.

Fig. IV is a fragmentary sectional view of the furnace structure, as seen on the plane IV-IV of Fig. III. I

Referring to the drawings, it will be perceived that the walls of the furnace 2 and the body of the car 3 are shown fragmentarily. Indeed, only the back wall 4 and one of the two side walls 5 of the furnace appear in the drawings, with the back end of the car shown fragmentarily. The front wall of the furnace, the door of the furanism for shifting the car into and out of the furnace, and such other conventional features of furnace construction as are not necessary to an understanding of the invention have been omitted from the drawings.

The means for sealing the car body to the furnace walls include, in accordance with usual practice, a steel channel 8 on each side of the car body, and this channel is filled with dry sand or other suitable luting material. Mountedon each side wall 5 of the furnace is a member 1 that extends the length of the furnace, and this member includes a continuous flange portion 10 which, when the car is moved into the furnace chamber, lodges in the sand in the corresponding channel 6 on the car, thus providing a seal between the side of the car body and the side wall of the furnace. The means for sealing the opposite side of the car to the opposite side wall of the furnace are identical with the channel and flanged member last described, and thus it is that both sides of the car body are sealed to the furnace walls.

Means are provided for sealing the back or inner end of the car body to the back wall of the furnace, and it will be understood that the door at the front of the furnace (not shown) engages the front end of the car, to complete the essential sealing of the car body to the furnace structure. The present invention is centered in the means for sealing the back end of the car body to back wall of the furnace.

Referring to Fig. I, a box-like container 8, formed of steel plate or cast steel, is built into the back or rear end of the car body. More specifically, an iron or steel casting 9, integrated with the container side walls and arranged to form a top wall for the container, includes a horizontal flange III thatis welded or otherwise united to the longitudinal beams N that provide the support for the refractory floor I2 of the car 3.

The cas i includes also a vertical flange it that later supports the terminal course of refractory blocks i l of the floor of the car. These blocks id are severally formed with downwardly convergent passages l5, and the casting 9 is provided with orifices that severally register with the bottoms of such passages. These registered passages and orifices provide inlet openings that are accessible externally of the car body, for the charging of sand id or other luting material into the container 8. eral passages 55 comprise a hopper in whicha relatively large supply of sand may be stored, whereby, regardless of the loss of sand that may" be occasioned when the caris moved into and out of the furnace, a single charging of the container is adequate for a prolongedcampaign of furnace operation.

The outermost wall of the container atlthe'endi of the car includes a slot [6 that extends the width of the car, and it is to benoted that, as viewed in Fig. III, the upper and-lower edges ii and i8, respectively, of this slot are so spaced apart that the plane defined by suchedges is in clined to the horizontal at angle that isno greater than, and preferably is less than, the angle of repose of the sand confined in the container whereby the loss of sand through theslot is inhibited.

The back wall l of the furnace carries a..blade- !9 which extends transversely of the. furnace chamber and projects'inward from theface of,

the wall 4 at the elevationof the slot lBZin the container 8. When the car is moved into. service position in the furnace, the otherwisefree edge. of the blade l9 enters the slot and embeds itself in the sand in the container, forming the desired seal between the end of thecarand the end wall of the furnace. Preferably, the lower edge of the slot it is reinforced by means of an inclined flange lil, and this flange assists in guiding the edge of the plate l9 into the slotl6, inthe' event that the blade should become warped Lmder the heat of the furnace; The upper edge I! of the slot IS'is formed by the inner'edge faeflange 2i that is inclined inwardly and downwardly'from' slotted wall of the container.

Asshown in Fig. III, the inner edge'of-fiange 2! is positioned close to the'upper surface of the blade 58 embeddedin the sand inthe container- 8, and thus it *is:that,1when the. candle withdrawnfrom the furnace and the blade emerges from the .slot l6, the loss'of sand from'the container is minimized; Indeed, the flange 2i may be formed of an'elastic'material, .such asheavy asbestos fabric, or other suitable; material, and as such the flange will operate as. a wiperrflap upon the surface of the blade l9, to prevent loss of sand when the blade is emerges'fromthe container.

To the end that the inner corners of the car body shall be perfectly sealedin' the-cornersformed 'bythe side and back Walls of'thefurnace, the blade or flange" portions'ld'of'the sealing members i carried by the furnace side walls are formed of increasedvertical extentin" the regions Ida (Fig. I), and are welded or otherwise secured and sealed, as at 22, tothe body of the sealing blade is. The sand-containing channels d'onthe sides of the .car arenslopeddownxward adjacent to the backiendof the'carlsee dotted lines 611 in Figs I and III), to provide clearance forthevertically widened portionsl'lila of the'side sealing members i. 'The inner verti-v cal wall'of each sand-containing'channel :6: is

The container 8 and the sevI--' slotted, as indicated at iii) in Fig. I, whereby the terminal portions of the blade it to which the flange portions lilo of the side sealing members are united, may enter the sand in the side channels 6 and thus provide a seal of uninterrupted continuity.

Manifestly, the construction and organization of the sealing" means are such that, when the furnace door (not shown) is opened, the car may 10 be moved into and out of the furnace chamber T without the sealing means requiring any attention. Theside sealing blade portions id simply cut as a' knife through the sand contained in thechannels ii on the sides of the car, and the end blade l3 readily enters and leaves embedded position in the: sand in the container 8. The advantages of the improvements herein described will be apparent'to'those skilled in the art.

From the foregoing specification, it will be seen that the furnace is constructed of two parts, the stationary furnace body 2 and the car i that is movable relatively thereto, The channels 6 andblades Id, carried respectively by the sides of the car and the side walls of the furnace, to provide theside sand seals, extend in parallelism with the direction of movement of the car i relatively to the-furnace body 2, while. the. end sand seal formed by the hopper-like structure as, it and the plate element is extend transversely of such direction of relative movement of the fur.-

nace parts. zontal wall of the container 8 below the opening or slot l6 provides afloorthat receives and holds the 'sand into which the plate element IS is in service embedded.

noted, beformed of steel plate, this being for the reason that such walls are not directly exposed to the heat radiated by the incandescent walls 1 of the furnace chamber during the work-heating cycle of furnace operation.v In the case of the blade or plate element iii, however, a portion of the blade [9 is exposed to the radiant heat of thefurnace, and for this reason it is desirable,

ifnot essential, to form such blade of cast iron or steel that possesses a much higher durability under heat thandces steel plate. The cast body of the blade Wis relatively rigid, while the steel body of thecontainer 8 is relatively elastic or flexible.- (particularly the slotted wall) of the container 8 is a desirable feature, since the body of the container is adapted to yield, in case the projecting edge of the blade l9 should engage the flange 2d when the cart is moved into service position in the furnace, and permit the slot 16 in the container to come to proper registry with the edge of theblade.

Various modifications in structure are permissible within the terms of the appended claims, without departing from the invention described.

I claim as my invention:

1. In a car-bottom furnace including a furnace sandcontainer carried by and extending across the back end of the car body and having a slot opening in the sand-confining wall exposed at such end of the car body, and a sealing member securedtoand extending from the back wall of the furnace chamber, the portion of said mem-' her extending from the furnace backwall being It will be perceived that the hori-f.

The walls of the-container 8 may, as above,

The elasticity or flexibility of the walls,

adaptedas the car is moved into service position within the furnace chamber'to move horizontally into said slot and lodge in car-sealing position in the sand in said container.

2. In a car-bottom furnace including a furnace chamber, a car movable into andfrom position of service within said chamber, and meansfor sealing the back end of the car body to the back wall of the chamber, the herein described improvement in such sealing means which comprises a sand container having a slotted wall carried by and extending across the back end of the. car body, and a blade sealed to and extending from the back wall ofthe furnace chamber, the otherwise free edge of said blade being adapted as the car is moved into service position within said chamber. to move horizontally into said slot and embed itself in car-sealing position in the sand in said container.

3. In a car-bottom furnace including a furnace chamber, a car movable into and from position of service within said chamber, and means for sealing the back end of the car body to the back wall of the chamber, the herein described improvement in such sealing means which comprises a slotted sand container carried by and extending across the back end of the car body, and a sealing member secured to and extending from the back wall of the furnace chamber, the portion of said member extending from the furnace back wall being adapted as the car is moved into service position within the furnace to enter said slot and lodge in car-sealing position in the sand in the container, said container comprising a hopper having a charging inlet accessible externally of the car body.

4. In a car-bottom furnace including a furnace chamber, a car movable into and from position of service within said chamber, and means for sealing the back end of the car body to the back wall of the chamber, the herein described improvement in such sealing means which comprises a transversely slotted sand container carried by and extending across the back end of the car body, and a sealing member secured to and extending from the back wall of the furnace chamber, the portion ofsaid member extending from the furnace back wall being adapted as the car is moved into service position within the furnace to enter said slot and lodge in car-sealing position in the sand in the container, the lower edge of the slot being horizontally offset from the upper edge of the slot, whereby the plane of the slot is inclined at an angle which is less than the angle of repose of the sand in said container.

5. In a car-bottom furnace including a furnace chamber, a car movable into and from position of service within the chamber, and means for sealing the car body to the side walls and back wall of such chamber, the herein described improvements in said sealing means comprising a channel containing sand extending along each side of the car, means carried by said side walls of the furnace chamber and adapted to enter the sand in said channels and seal the sides of the car body to the side walls of the furnace chamber, a sand container secured to and extending across the back end of said car and including in the rear wall thereof a slot extending the width of the car, and a sealin member secured to and extending from the back wall of the furnace chamber, the portion of said member extending from the furnace back wall being adapted as the car is shifted into service position within the furnace chamber to move horizontally into said slot and lodge in car sealing position in the sand in i the container to cooperate with the said sealing means at the sides of the car in sealing the car body to said walls of the furnace chamber.

6. The structure of claim 5, said sand container on the back end of the car comprising a hopper having a charging inlet accessible externally of the car body.

7. In a car-bottom furnace including a furnace chamber, a car movable into and from position of service within the chamber, and means for sealing the car body to the side walls and back wall of said chamber, said means including on each side of the car a longitudinally extending channel containing sand, a member including a vertical flange portion carried by and extending outward from each of the furnace side walls, each of said flange portions being adapted at its outer edge to lodge in the sand contained in the chan nel on the corresponding side of the car, whereby the two sides of the car body are sealed to the side walls of said furnace chamber, a sand container extending across the back end of said car, said container including in the rear wall thereof a transversely extending slot, a transverse blade secured to and extending horizontally from the back wall of the furnace chamber, the otherwise free edge of said blade being adapted as the car is moved into service position within said chem her to enter said slot and lodge in the sand in said container, to seal the back end of the car body to the back wall of the furnace chamber.

8. In a car-bottom furnaceincluding a furnace chamber, a car movable into and from position of service within the chamber, and means for sealing the car body to the side walls and back wall of said chamber, said means including a longitudinally extending channel containing sand on each side of the car body, a member including a vertical flange portion carried by and extending outward from each side wall of the furnace chamber, each of said flange portions being adapted at its outer edge to lodge in the sand contained in the channel on the corresponding side of the car, whereby the two sides of the car body are sealed to the side walls of said furnace chamber, a sand container extending across the back end of said car, said container including in the rear wall thereof a transversely extending slot, a transverse blade secured to and extending horizontally from the back wall of the furnace chamber, the otherwise free edge of said blade being adapted as the car is moved into service position within said chamber to enter said slot and lodge in the sand in said container, to seal the back end of the car body to the back wall of the furnace chamber, said flange portions on the side walls of said chamber, embedded at their edges in the sand in the channels on the two sides of the car, making sealed engagement with the blade carried by the back wall of the furnace chamber.

9. In a furnace structure having relatively movable parts, cooperating means on said parts for establishing a sand seal that extends transversely of the direction of relative movement of the parts, said means comprising a projecting horizontal plate element on one of theparts, and a hopper-like structure containing sand on the other of said parts, said hopper-like structure having an opening into which the plate element of the other furnace part may project, there being means below said opening forming a bottom for the hopper to receive and hold the sand.

10. In a furnace having relatively movable inner and outer parts of substantially rectangular contour, and'means-for sealing tneparts-in. telescopically assembled position; the;--herein;de-'= scribed invention in said means; comprising "sandcontainers extending along. eachof-the two, sides" and across one end-of the inner furnace part,jvertical blades extending along the; two sides: of' the. outer furnace part and being removablyt embedded in the sand in the containers on the-sides of the inner furnace part, 'said container-on the end ofthe inner furnace part having an epening IDA-N b extending longitudinally between the -containers 0n the oppositesides of said inner furna-eepart, and a-horizontal blade member extendingb.91-

tween: and securedto said vertical blades of the outer furnace part and beingmovable through said opening into embedded. position. in-the-sand inthe container on the end'of the inner furnace part, said vertical and. horizontal blades providingiaicontinuous sealing-blade around said sides and Qlidflf the outer furnac pe v QHN C; PIPER.

REFERENCES CITED The followingreferences are of record in the file 0f this patent:

UNITED STATES PATENTS 

